The battery in a modern automobile is not of very modern technology. Despite promises of atomic cars and everlasting power, the old tech lead-acid battery still rides under many hoods. So-called maintenance-free batteries are really just updated versions of the first automotive lead-acid battery used to kick over a production Cadillac in the year of 1912. While design improvements have of course been made, the automobile battery still requires occasional help. Regular battery inspection and maintenance can make the difference between a five-year battery lasting five years, and a battery that gives up a year or so after purchase on a wicked cold night in a dark far corner of the airport long-term parking lot.

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Suspended inside the plastic shell of the battery are lead plates coated with particular metals. These plates react with the battery acid, or electrolyte solution, to produce and store electricity. As the battery charges during driving some electrolyte vapor vents out of the plastic shell along with a bit of hydrogen. This vapor can cause corrosion to form around the battery terminals and posts along with causing nasty things to happen under the battery tray. Snowy corrosion on the posts and terminals can interrupt the flow of electricity into and out of the battery. Electrolyte levels drop as the solution evaporates and leave the battery unable to hold or take a charge. Battery cleaning and maintenance will help keep a lid on these problems.

Install safety glasses, gloves, and disposable clothing on yourself before doing any battery work. In case you were asleep in Chemistry class, or forgot about the cover of Led Zeppelin 1, hydrogen explodes handily in the presence of spark. The combination of potential explosion and corrosive acid is why keeping tools off the top of the battery and out of your hands when you're not using them is a good plan. Metal tools making contact across battery posts will produce a shower of sparks.

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There are a few different configurations of the terminal-and-post arrangement. They all work to the same end. Loosen terminal bolts and remove negative battery terminal first. The negative is marked with the (-) symbol, by the color black, or green. Give terminal a good twist to break any corrosive hold on the post. Spread apart old-style terminals with flat blade screwdriver if stubborn. Remove positive terminal in the same way. The (+) symbol or the color red distinguishes the positive terminal.

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Clean up the battery posts and terminals. All manner of tools designed specifically for this task are available in at your local auto parts store. Use the tool until the metal of the posts and terminals are shiny and free of corrosion. Shown here is the post end of things. Use the other end for cleaning the inside of the terminals.

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Remove battery caps. Add only distilled water to slightly below fill hole. Never overfill a battery, or use tap, spring, or vitamin water. Hydrogen gas needs room to vent. Minerals in tap water can react adversely with the battery acid and lead plates and cause the battery to become uncooperative. Battery fillers are inexpensive and well suited to the task. Turkey basters or similar, will also work. Just don't use it for basting anymore after contact with battery acid.

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Loosen and remove the battery hold downs. The hold-downs keep the battery from knocking about under the hood. Look for a strap-type bar with a few bolts or wingnuts. Remove the battery. Clean the battery and battery tray area with solution of one-pound baking soda to one gallon of water to help neutralize acid and prevent corrosion. Dry or allow to dry before reassembling.

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Re-install the battery coat posts and terminals with a dielectric grease to help prevent corrosion and aid in conductivity. Petroleum jelly will also work. Spread the grease in a thin coat over both posts and terminals. Now is also a good time to employ a battery charger if required.

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Always replace any broken or crumbling terminals. Felt pads under the terminals fight corrosion and keep positive-negative post-terminal confusion to a minimum. Install terminals on posts using downward force and a twist for good contact. Tighten up the bolts. Snug is good. Don't overtighten the bolts.